LArTPC: Large Liquid Argon TPC for the NuMI Offaxis Beam

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LArTPC Large Liquid Argon TPC for the NuMI
Off-axis Beam
Context Neutrinos and Fermilab etc Status
Report on LArTPC Activities
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Synopsis

• This talk presents some of the efforts of the
  LArTPC group which is pushing the development of
  large liquid argon TPCs. Our small group is
  currently composed of 6 University groups and 6
  Fermilab staff physicists, but the number of
  people is growing.
• Large neutrino detectors, including large liquid
  argon TPCs, clearly are needed for upcoming
  neutrino experiments and into the neutrino
  factory era.

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ICARUS

• The LArTPC group recognizes that the technical
  concept and any possibility that such a detector
  may be feasible owes a huge debt to the work done
  by the ICARUS collaboration.

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The Big Picture
Sensitivity detector mass x detector
efficiency x protons on target/yr x of years
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The promise of liquid argon
Electrons compared to p0's at 1.5 GeV in LAr TPC
Dot indicates hit, color is collected
charge green1 mip, red2 mips (or more)
X plane
X plane
cm
cm
zoom in
zoom in
U plane
cm
U plane
cm
zoom in
zoom in
p0 Multiple secondary tracks pointing back to the
same primary vertex Each track is two electrons
2 mip scale per hit
Electrons Single track (mip scale) starting from
a single vertex
use both topology and dE/dx to identify
interactions
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The promise of liquid argon
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Jim Strait to Fermilab PAC June 20, 2005 Head
of Particle Physics Division
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P. Oddone September 12, 2005
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P. Oddone September 12, 2005
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P. Oddone September 12, 2005
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P. Oddone September 12, 2005
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P. Oddone September 12, 2005
A Large Liquid Argon TPC for the NuMI Off-axis
Beam is part of a plan at Fermilab
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LArTPCs report to NuSAG
Fermilab Note FN-0776-E A Large Liquid Argon
Time Projection Chamber for Long-baseline,
Off-Axis Neutrino Oscillation Physics with the
NuMI Beam Submission to NuSAG September 15,
2005 D. Finley, D. Jensen, H. Jostlein, A.
Marchionni, S. Pordes, P. A. Rapidis Fermi
National Accelerator Laboratory, Batavia,
Illinois C. Bromberg Michigan State University C.
Lu, K. T. McDonald Princeton University H.
Gallagher, A. Mann, J. Schneps Tufts
University D. Cline, F. Sergiampietri, H.
Wang University of California at Los Angeles A.
Curioni, B. T. Fleming Yale University S.
Menary York University Contact Persons B. T.
Fleming and P. A. Rapidis
Soon to be on the hep-ex preprint server
The Neutrino Scientific Assessment Group for
the DOE/NSF
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NuMI Liquid Argon TPC Overview
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NuMI Liquid Argon TPC Overview
Note At this point in time 15 could be
50 1 could be 3 etc
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The Large Liquid Argon TPC
Aim is to produce a viable design for a 15 kt -
50 kt liquid argon detector. Basic concept
follows ICARUS TPC, drift ionization electrons
to 3 sets of wires (2 induction, 1
collection) record signals on all wires with
continuous waveform digitizing electronics Differ
ences aimed at making a multi-kton detector
feasible Construction of detector tank using
industrial LNG tank as basic structure
Long(er) signal wires Single device (not
modular) Basic parameters Drift distance - 3
meters Drift field - 500 V/cm (gives vdrift
1.5 m/ms) Wire planes - 3 (/-300 and
vertical) wire spacing 5 mm plane spacing 5 mm
Number of signal channels 100,000 (15kt),
220,000 (50kt) LRadiation 14 cm, dE/dx
2.1 MeV/cm, 55,000 electrons/cm liberated
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The Large Liquid Argon TPC
Some Specific challenges Argon (long drift)
purification - starting from atmosphere (cannot
evacuate detector tank) -
effect of tank walls non-clean-room assembly
process Wire-planes
long wires - mechanical robustness, tensioning,
assembly, breakage/failure Signal
processing electronics - noise due to
long wire and connection cables (large
capacitance) surface detector -
data-rates, - automated cosmic ray
rejection -
automated event recognition and reconstruction
(and there are others for example, High
Voltage)
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Detector Tank based on Industrial Liquefied
Natural Gas (LNG) storage tanks
Many large LNG tanks in service. excellent safety
record
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The Large Liquid Argon TPC Sketch
3D Model cutaway 15 kt detector
S i g n a l
H V
Changes from standard LNG tank inner tank wall
thickness increased - LAr is 2 x density of LNG
trusses in inner tank to take load of the
wires penetrations for signals from inner tank
to floor supported from roof of outer tank

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The Large Liquid Argon TPC Beams Eye View
Beams eye view showing the electrodes (cathode,
field-cage and wires)
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The Large Liquid Argon TPC Site Features
Site Layout (very) Schematic showing some of
the services needed
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On the way to the Large Liquid Argon TPC
Note At this point in time 15 could be
50 1 could be 3 etc
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The Purposes of the 1 kton tank

• Engineering Development to demonstrate
  scalability to large tank
• Construction of tank with the same techniques to
  be used with the large tank
• Demonstrate argon purity with the same techniques
  to be used with the large tank
• Mechanical integrity of TPC
• Readout signal / noise
• Microphonics due to argon flow
• Uncover whatever surprises there may be

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The Purposes of the 130 ton detector(50 ton
fiducial)

• Physics development using existing technology
• Record complete neutrino interactions (nm and ne)
  in a high intensity beam
• Establish physics collaboration by
• Developing event identification
• Developing reconstruction
• Developing analysis
• Establish successful technology transfer

What Energy to pick?
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NuMI Off-axis Neutrino Energy
From the NOvA Proposal March 15, 2005

• CC nm event rate for
• - NuMI medium energy beam
• No-oscillation hypothesis
• 800 km from Fermilab for various off-axis angles

The event spectrum in the 14 mrad off-axis beam
peaks at about 2 GeV, and there are more events
than at 0 mrad.
Pick 2 GeV. Where can we get 2 GeV today?
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NuMI Beamline and Surface Building
From the NOvA Proposal March 15, 2005
The MINOS Near Detector Hall is 105 meters
BELOW the Surface Building
hadron absorber
The NuMI decay pipe is 675 m long
The 130 ton LArTPC detector would go in or near
the MINOS Surface Building.
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Electron Neutrinos in MINOS Surface Building
NuMI is presently providing 2E20 POT per
year. The 130 ton LArTPC has a 50 ton fiducial
mass. Thus the LArTPC detector would get 1600
ne events / year.
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Muon Neutrinos in MINOS Surface Building
From the NOvA Proposal March 15, 2005
Same assumptions as previous slide, except this
shows 15,000 muon neutrinos. The nm peak at 2.8
GeV is from Kaon decay.
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NuMI Liquid Argon TPC Getting Started
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Materials Tests
System at Fermilab for testing filter materials
and the contaminating effects of detector
materials (e.g. tank-walls, cables)
ICARUS purity monitor
G. Carugno et al., NIM. A292 (1990
Test Samples Dewar
Filter
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Materials Tests
setup for lifetime measurements (effect of
materials and effectiveness of different filters)
under assembly at Fermilab.
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LArTPC Test Setup at Yale
Purity monitor in liquid argon
Purity and light collection
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5 m Drift Demonstration at Fermilab
Cryostat drawing for purchasing department
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Long Wires Tests

• Wire Planes
• Induction (2 /- 30) and Collection Planes
  spaced by 5 m
• 5mm pitch within planes
• 220,000 signal wires total (50 kTon), 100,000
  signal wires (15 kTon)
• Longest wire 35 meters (50 kTon) , 23 meters
  (15 kTon)
• Need to be robust - no breakages
• Need practical assembly and installation
  procedure.
• Wire Material 150 micron Stainless
• Present Concept (different from ICARUS)
• Tension implemented by attaching a weight to each
  wire (1kg) to avoid tension changes due to
  temperature changes.

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RD path shaped by open questions for large
detectors (part 1)

• Key Hardware Issues
• Technology transfer
• Begin Technical Setups at Fermilab
• Seeing tracks and light production at Yale
• Understanding long drifts (5 m)
• Purity tests setups at Fermilab
• Introduction of impurities, test of detector and
  tank materials
• Test of filtering materials, demonstrate
  purification rate
• Very long wire electrode assembly/stability and
  readout
• Design for detector to be assembled with
  industrial techniques

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RD path shaped by open questions for large
detectors (part 2)
Key software issues Simulation Monte
Carlo(s) Reconstruction / automated event
reconstruction Physics analysis Key
collaboration and physics issues Developing
defensible cost and schedule Growing a strong
collaboration Navigating a global, developing,
exciting neutrino physics program
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Final Slide
Receiving support from Fermilab both in
engineering and with recently increased
funding Growing support from University groups
in smaller technical setups, software efforts,
etc Receiving generous support for technology
transfer from experts in Europe, and hoping to
learn more from ongoing tests Hoping for
continued interest from the US Government for
neutrino physics in general and LArTPCs in
particular Continuing along the path to develop
Large Liquid Argon TPCs - not only in the
ongoing NuMI era, but also into the neutrino
factory era, and for other physics Would like to
develop our efforts with wider participation
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Back- ups, extras
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Large Liquid Argon TPC for the NuMI Off-axis Beam
everything about drifting in one fine slide
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towards a Large Liquid Argon TPC for the NuMI
Off-axis Beam
Liquid Argon purity requirements
purity/lifetime requirements for lt20 signal
loss 3m drift -gt 10 ms lifetime 30 ppt
2m drift -gt 6 ms lifetime 50 ppt
1m drift -gt 3ms lifetime 90 ppt

ICARUS achieved 10 ms in 1997 T600 lifetime
evolution implies gt10 ms asymptotic value
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towards a Large Liquid Argon TPC for the NuMI
Off-axis Beam
Electronics and Data Acquisition Summary
Electronics ICARUS scheme - an intelligent
waveform recorder on each wire Amplifier
sensitivity achieved in existing custom devices
for this capacitance (S/N) 22,000 e / 2500 e
8.5/1 - digitize with commercial ADCs
adequate performance, reasonable cost -
intelligence from commercial FPGAs adequate
performance, reasonable cost. Data
Acquisition Use commercial switches and
multiplexors Have a design to achieve 5
Gbyte/second into 200 PCs for reasonable cost.
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towards a Large Liquid Argon TPC for the NuMI
Off-axis Beam
Data Acquisition schematic
Raw data rate nwires x 2.5 MHz need 2 bytes
per sample WFT (Wave Form Train) is all the
digitizings Zero suppression Cosmic ray rate
is 200 kHz each ray 5000 signals, Set
intelligent threshold in FPGA, pass next 40
samples DAT (Data Above Threshold) Processing
each hit fully in FPGA to return pulse-height and
time requires 4 bytes/hit FHP (Full Hit
Processing)
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towards a Large Liquid Argon TPC for the NuMI
Off-axis Beam
50 kt data rates
exceeds bandwidth of 5 GB/sec
Note Full hit processing allows for Always Live
running
Spill Only looks at 4 milliseconds (to see
events plus any early cosmic rays) each spill
(every 2 seconds)
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Large Liquid Argon TPC for the NuMI Off-axis Beam
Simulation Results
LArTPC Total absorption calorimeter 5mm
sampling -gt 28 samples/rad length Excellent
energy resolution First pass studies using hit
level MC show 81 7 ne efficiency and
Neutral Current rejection factor 70 (only need
NC rejection factor of 20 to reduce NC background
down to ½ the intrinsic ne rate)
high ne efficiency good NC rejection
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Large Liquid Argon TPC for the NuMI Off-axis Beam
Efficiency and Rejection study
Tufts University Group
Analysis was based on a blind scan of 450 events,
carried out by 4 undergraduates with additional
scanning of signal events by experts.
Neutrino event generator NEUGEN3, used by
MINOS/NOvA collaboration (and others) Hugh
Gallagher (Tufts) is the principal author.
GEANT 3 detector simulation (Hatcher, Para)
trace resulting particles through a homogeneous
volume of liquid argon. Store energy deposits in
thin slices.

• Training samples
• 50 events each of neCC, nmCC and NC
• individual samples to train
• mixed samples to test training
• Blind scan of 450 events
• scored from 1-5 with
• signal5
• background1

nmCC
NC
log scale
open region students hatched region experts
neCC
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Large Liquid Argon TPC for the NuMI Off-axis Beam
Overall efficiencies, rejection factors,
and dependencies

Signal ne
eff.
Event type
signal ne
Efficiency is substantial even for high
multiplicity (DIS) events
Efficiency is 100 for ylt0.5, and 50 above
this
Overall efficiency 81 /- 7 Rejection of NC is
73 (60,-30)
yEhad/En
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LArTPC work underway at Yale How good are these
detectors at IDing low (1 GeV) energy n
interactions?

• understand the technology
• purity studies
• understand detector response at very low energies
• study combination of charge and light production
  for particle ID

Bartoszek Engineering
Work funded by DOE Advanced Detector Research
Grant
Constructing small prototype vessel this summer